introduction to organic chemistry

Question 1

what is the definition of functional group?

Answer 1

the atom or group of atoms that is responsible for most of the chemical reactions of a molecules

Question 2

what’s the definition of homologous series?

Answer 2

a family of compounds with the same general formula and similar chemical properties

Question 3

what is the definition of hydrocarbon?

Answer 3

molecules containing hydrogen and carbon only

Question 4

what’s the definition of stereoisomers?

Answer 4

molecules with the same molecular and structural formulae but a different spatial arrangement of atoms

Question 4

what is the definition of saturated?

Answer 4

molecules containing no double bonds

Question 5

what is structural isomer?

Answer 5

molecules with the same molecular formula but different structures

Question 6

what is chain isomer?

Answer 6

structural isomers that differ by having a different carbon chain

Question 7

what is position isomer?

Answer 7

structural isomers that differ by having the functional group in a different place

Question 8

what is functional group isomer?

Answer 8

structural isomers that differ by having a different functional group

Question 9

what is molecular formula?

Answer 9

formula that gives the actual number of atoms of each element in one molecule

Question 10

what is the empirical formula

Answer 10

formula that gives the simplest ratio of atoms of each element in a compound

Question 11

what is the structural formula?

Answer 11

this shows how the atoms are joined together in a molecule

Question 12

what is the displayed formula?

Answer 12

this shows all the bonds and atoms in a molecule

Question 13

what is the skeletal formula?

Answer 13

this uses lines to represent bonds. each point represents a c atoms

Question 14

what are alkanes a homologous series of?

Answer 14

-saturated hydrocarbons with the general formula CnH2n+2.
-this means that they are made of hydrogen and carbon only and contain only carbon-carbon single bonds

Question 15

what properties will alkanes have since they’re from the same homologous group?

Answer 15

• same functional group
  -same general formula
  -same chemical properties
  -differ in their chemical formula by one CH2 group
  -have gradually changing physical properties

Question 16

how do you name alkanes?

Answer 16

1. of their are any side chains/functional groups present then the position of these groups is indicated by numbering the carbon atoms in the longest chain starting at the end that gives the lowest possible numbers in the name
   2.the hydrocarbon side chain is shown in brackets in the structural formula
   3.the side chain is named by adding “yl” to the normal alkane stem. This type of group is called an alkyl group
   4.if there are more than one of the same alkyl side chain or functional groups, di (2), tri (3) or tetra (4) is added in front of its name
2. the adjacent numbers are separated from words by a hyphen
3. if there is more than one type of alkyl side chain, they are listed in alphabetical order

Question 17

different types of functional group

Answer 17

C=C in alkenes
OH in alcohols

Question 19

how do you name halogenoalkanes?

Answer 19

1.Name the longest carbon chain in the compound and add the suffix “-ane”.
2.Add a prefix to indicate the halogen atoms:
* Fluoro: For fluorine
* Chloro: For chlorine *Bromo: For bromine
* lodo: For iodine
3. The functional is indicated by a prefix or suffix. e.g. chloroethane
4. The position of the functional group is given by a number, counting from the end that gives the functional group the lowest number
5. Where there are two or more of the same groups, di, tri- or tetra are used.
6. If there is more than one functional group, numbers are separated by commas and the groups are listed in alphabetical order (ignoring di, tri, etc.).
7. If a number is not necessary (i.e. the group could only be in one place) then no number should be given.
8. Numbers are separated by commas and word and numbers by dashes

Question 20

why is 1-chloropentane and 2-chloropentane position isomers?

Answer 20

they have the same molecular formula but the chlorine atoms is attached to a different carbon atom

Question 21

what are the 3 different types of halogenoalkane?

Answer 21

positioning of the halogen atoms is used to classify halogenoalkanes
1.primary (1°) halogenoalkane- carbon joined to halogen is attached to one other alkyl group
2.secondary (2°) halogenoalkane- carbon joined to halogen is attached to two other alkyl groups
3.tertiary (3°) halogenoalkane- carbon joined to halogen is attached to three other alkyl groups

Question 22

what are the properties of alkenes

Answer 22

*Alkenes are unsaturated hydrocarbons with at least one carbon-to-carbon double bond.
* Alkenes are hydrocarbons (i.e. made up of carbon and hydrogen atoms).
* Alkenes are more reactive than alkanes because of the double bond.
* Alkenes can undergo addition reactions, where one molecule combines with another to form a larger molecule. For example, alkenes can react with hydrogen to form alkanes.
* Alkenes can be used to produce addition polymers, which are used to make plastics.
* Alkenes have lower boiling points than alkanes, but the boiling point increases as the size of the molecule increase

Question 23

how do you name alkenes

Answer 23

*Find the longest carbon chain that contains the double bond
* Name like an alkane but use - ene. Use “-diene” for two, or “-triene” for three double bonds.
* Number the carbons so the double bond carbons have the lowest possible numbers.
* State the number before the -ene with a dash, e.g. hex-1-ene
Remember to name side chains and the double bond as low as possible

Question 24

what are the 2 types of stereoisomerism?

Answer 24

1. E-Z isomers: caused by molecules with a C=C with two different groups attached to each C of the C=C
2. optical isomers: caused by C with atoms having four different groups attached leading to molecules that are non superimposable mirror images of each other

Question 25

how do you determine which group has the highest priority in E-Z isomer?

Answer 25

- look at the atoms directly attached to a C atom and the highest atomic number has the HP - if there's a tie then consider the atoms at distance 2 from the stereo centre as a list is made for each group of the atoms - each list is arranged in order of decreasing atomic number - the lists are compared atom by atom, at the earliest difference the group containing the atom of higher atomic number receives higher priority

Question 26

how to determine if a molecule is E or Z isomer?

Answer 26

1. Z isomer = highest priority or same atom skis on the same side 2. E isomer = if the highest priority or atom is on opposite sides

Question 27

how do you work out the empirical formula of a molecule?

Answer 27

1. work out the percentage or mass of each atom 2. divide it by the Ar of the element not the Mr 3. find the simplest whole number ratio of these numbers by dividing by the simplest smallest number 4.if the values come out as n ear as 1/2 then times 2, if they're near 1/3 then times by 3 5. never leave the values as a decimal in the end and only round on the last step

Question 28

how to find the molecular formula?

Answer 28

-divide the relative formula mass of the molecular form ula by the relative mass of the empirical formula -multiply the number of each element present in the empirical formula by this number to find the molecular formular

Question 29

what's the formula for percentage yield?

Answer 29

percentage yield=actual yield divide theoretical yield X 100

Question 30

why might you not get all the expected amount of product when you make a new substance by a chemical reaction?

Answer 30

1. Incomplete Reactions: Some reactions don’t go to completion 2.Side Reactions: Unintended reactions might occur, forming by-products and reducing the amount of your desired product. 3.Loss of Product During Processing: Transferring, filtering, or purifying substances can cause small amounts of product to be lost. 4.Impure Reactants: If your starting materials aren’t 100% pure, the actual amount of reactants available is less than you calculated, so you form less product. 5.Measurement Errors: Mistakes in measuring or weighing chemicals can throw off your amounts. 6.Reversible Reactions: If the reaction is reversible, some of the product might convert back into reactants, lowering the yield. 7.Gas Loss (for gaseous products): If your product is a gas, some may escape before you can measure it, reducing the amount collected.

Question 31

what is atom economy used for?

Answer 31

- analyse the efficiency of reactions - most reactions produce more than one product and very often some of them are not useful - atom economy studies the amount of reactants that get turned into useful products - it illustrates the % of the mass of reactants become useful products - used to obtain sustainable development - important analysis for economic reasons as companies prefer to use these processes with higher atom economy - the higher the atom economy of a process then the more sustainable that process is - no atom are gained or lost in the reaction

Question 32

what's the formula for atom economy?

Answer 32

atom economy= total Mr of the product divide total Mr of all reactants X 100